Tube construction for automatic production



Feb. 4, 1958 P. KosKos ET AL 2,822,498

I TUBE CONSTRUCTION FOR AUTOMATIC PRODUCTION Filed April 19, 1954 2 She'ets$het 1 INVENTOR JQS'EP/f J. /5015 JR. BY PAUL kos/(as F -4,1958 P. KOSKQS Em 2,822 4 8 TUBE CONSTRUCTION FOR AUTOMATIC PRODUCTION Filed April 19, 1954 2 Sheets-Sheet 2 NVENTORS I JOSEPH J. /.$'0LE,JR. BY PAUL KOSKOS Ania biz United States Patent TUBE CONSTRUCTION FOR AUTOMATIC PRODUCTION Paul Koskos, Wiliiston Park, and Joseph J. Isole, Jr., Pelham, N. Y., assignors to Sylvania Electric Products Inc, a corporation'of Massachusetts Application April 19, 1954, Serial No. 424,063 Claims. (Cl. 313-250) The invention relates to tube construction of the laminated type, i. e., of the type wherein electrodes in laminar form are placed in close parallel relationship to one another.

It is an object of this invention to provide such a construction wherein assembly of parts is made particularly easy or as to lend itself to automatic machine production.

It is a further object of the invention to provide for improved cathode heater efiiciency.

It is a still further object of the invention to provide for exceedingly small interelectrode capacitances.

Yet another object of the invention is to provide for small spacing between cathode and-control grid and yet avoid shorting of these electrodes on heating of cathode.

These and other objects will be apparent after reading the following specification in conjunction with the accompanying drawing in which:

Fig. l is an exploded view of a tube mount and stem, withthe mount shown in cross section.

Fig. 2 is a side elevation of a mount and stem.

Fig. 3 is an elevation of the mount and stem at right angles to Fig. 2, and

Fig. 4 is a section on the line 4-4 of Fig. 2.

Referring to the drawings more in detail, at it there is shown a wafer or stem having a number of leads 12 extending therethrough.

Welded to each of two short leads 14 is a sleeve 16, the sleeve extending above the top of the leads to receive pins 18 provided near their lower ends with lateral projections or extrusions and which may be integral beads 20, the beads resting on the sleeves and the pins extending into and welded to the sleeves.

Threaded over the pins and supported by the beads is an anode 22, see Fig. l, of channel form to give it strength, the flanges 24 of the channel facing downward and the web portions 26 having a plateau 28. The anode has one hole 30 closely fitting a pin and a second hole 32 which, for a duo-triode construction, is larger than the pin 18, the pinbeing spaced from the anode 22 through the intermediary of a ceramic bushing 3 flush with the top of the web portion. Mounted on the pins 18, and resting on the anode 22 is a'pair of ceramic sleeves 36, of steatite, alumina or. the like, thesesleeves being of a length to accommodatea number of ceramic rings or washers and electrodes in stacked relation as will be set forth. Surrounding the sleeves and resting on the anode is a pair of ceramic washers 38, the washers being slightly thicker than the height of the plateau 28 above the web of the anode and determining by their thickness the close spacing of the anode from the adjacent electrode. Resting on these washers is a grid 46 comprised of a metallic or metal'coated' ceramic frame 42 and grid wires 44 brazed to one face of the frame. The frame has notched ends 46 snugly embracing'the sleeves 36 and resting on the washers 38 with the grid wires on the upper face of the frame. The frame is further provided with a tab 47 for electrical connection with a stem lead 12 and formed of a material to efiiciently conduct the heat away from the grid to the stem lead.

Placed on top of the grid 40 and surrounding the sleeve 36 is a second pair of ceramic washers 48 and mounted on the washers is a cathode assembly 50 comprised of two plates 52 integrally joined to one another as by welding along their edges. These plates are essentially rectangular in form and have notched ends 54 registering with the notches 46 in grid 40, the plates being dished with the hollow portions facing each other. The welding causes a rigid structure to be provided which is nonwarping even when heated. The notched ends allow for expansion of the plates when heated, the notched ends sliding between the adjacent. washers even with a tight assembly of parts. Thusprovision' is made for expansion of the cathode to prevent such lateral expansion as would cause buckling toward an adjacent grid. Within the hollow portion of the plates is an insulated heater 56, the legs of the heater passing out of the plates via circular duct portions 58. These duct portions lead to positions close to the pin leads, to which the filament tabs are welded, to electrostatically shield the filament from the remainder of the mount. Other symmetrical duct portions are formed for rib strengthening the cathode to prevent warping of the cathode on heat expansion and to cause expansion to take place solely parallel to the plane of the cathode. The grid wires on the grid frames 42, it will be'noticed, are placed close to the surface of the cathode, the spacing being determined by the thickness of washers 48. This provides for a tube of reproducible characteristics, easy assembly, and stable characteristics during operation. The cathode is. provided with a tab 60 of poor heat conductivity for welding: to a wafer lead 12, and, likewise, the filament legs are provided with tabs 62 for electrical connections with other leads." This? completes one triode section of the tube mount. A sec ond triode section may be provided by. continuing the stacking of elements on thesleeve. Continuing the stack ing operation, a thin pair of washers 64, similar to washers 48 is placed on the cathode, followed by a gridv 66- with brazed on wires facing the cathode on the washers and with its notched ends embracing the sleeve 36. The. second grid is provided with a tab 68 similar to tab 47 but in the case of a duo-triode, the tab is connected with a pin other than the one to which'tab 47'is connected. A fourth pair of ceramic washers 7%, similar to washers 38, is placed on the grid 66 and around the sleeve 36, and then a second anode 72, similar to anode 22, is threaded over the base pins 18. In the case of a duotriode, a hole 74 in the anode is made larger than the other hole in. the anode and a ceramic collared bushing '76 is slipped into the hole and over the pin 18 in the hole with'the collar uppermost. The pin 18 last referred to is the one in electrical contact with anode 2. The other pin 18 is out of electrical contact with anode 22 byreason ofbushing 34 but does make electrical contact with anode 72;.- The-upper ends of pins 18 are swaged over the collar of the bushing76and the anode 72, respectively, by the: application of heatand pressure while the parts of the mount are held tightly together by, any suitable-means; If desired thin metal washers may be interposed between the swaged over pin and the bushing. A support rod 78 is then welded to one of the pins, 18 and a getterassembly, 80 welded to the rod. a

It will be noted that all of the parts are assembled by right line motion with insulators, and electrodes merely stacked on one another. and that then all parts,are.com pacted into a unitary whole by swaging over theupper. ends of the two pins 18. The concave portions 46' and,54, of the grid and the cathode structures provide for ease, in assembly and yet prevent excessive longittidinal 'distherefore a rigidly held together compact assembly. If desired, the whole electrode structure may be assembled on the pins 18, with the pins temporarily firmly held in a ig or support and then, after fastening together the parts, the pins 18 may be set into the sleeves 16 which previously had been slipped over the'leads 14 of the stem and then the pins may be secured to the sleeves.

The whole stacked structure of the mount with the very close but yet accurate spacing of parts enables tubes to be manufactured either by manual assembly of parts or by automatic machinery, the tube being rugged and adapted for use in very high frequency circuits and with very high gain. The two pin support provides for a minimum amount of leakage and yet offers sufficient rigid support for the mount.

Having thus described our invention, what we claim is:

l. A tube comprising, a pair of pins, said pins having fixed lateral extruding portions near their lower ends, an anode structure supported by said extrusions, a long ceramic spacing sleeve about each of the pins on top of the anode structure, a short ceramic washer about each of said sleeves and resting on the anode structure, a flat grid frame with lateral grid wires and having notched ends partially surrounding the ceramic sleeves and resting on the ceramic washers, a heat radiating and electro-conductive tab fastened to said grid frame and fastened to a lead of a stem to which the assembly is secured, a second pair of short washers surrounding the ceramic sleeves, a cathode assembly comprising opposed dished plates fastened together forming a hollow interior with an insulated heater therebetween and with notched ends symmetrical with the notched ends of the grid frame surrounding the ceramic sleeve and resting on said second pair of washers, and said cathode having a tab connected with another of the leads of the stem with said filament connected with still other leads.

2. A tube comprising a pair of pins, said pins having fixed bead portions near their lower ends, an anode structure supported by said beads, said structure having a flat topped raised portion, a long ceramic spacing sleeve about each of the pins on top of the anode structure, a short ceramic washer about each of said sleeves and resting on the anode structure, a flat grid frame with lateral grid wires on the face of the frame away from the anode and having notched ends partially surrounding the ceramic sleeves and resting on the ceramic washers, said raised portion on the anode extending close to the frame but out of contact therewith, a heat radiating and electroconductive tab fastened to a side of said grid frame and fastened to a lead of a stem to which the assembly is to be secured, a second pair of short washers surrounding the ceramic sleeves, a cathode assembly comprising opposed dished plates fastened together forming a hollow interior with an insulated heater therebetween and with notched ends symmetrical with the notched ends of the grid frame surrounding the ceramic sleeve and resting on said second pair of washers, and said cathode having a tab connected with another of the leads of the stem with said filament connected with still other leads.

3. A tube comprising, a pair of pins, said pins having fixed lateral extruding portions near their lower ends, a channel shaped anode supported by said lateral extrusions with the channel sides extending downward and the web in a horizontal plane, said web having a flat topped central portion raised above the general level of the web portion, a long ceramic spacing sleeve about each of the pins on top of the anode, a short ceramic washer about each of said sleeves and resting on the anode, a flat grid frame with lateral grid wires on the face of the frame away from the anode and having notched ends partially surrounding the ceramic sleeves and resting on the ceramic washers, said raised portion of the anode extending close to the frame but out of contact therewith, a heat radiating and electro-conductive tab fastened to a side of said grid frame and fastened to a lead of a stem to which the assembly is to be secured, a second pair of washers surrounding the ceramic sleeves, a cathode assembly comprising opposed dished plates securely fastened together forming a hollow interior with an insulated heater therebetween and with notched ends symmetrical with the notched ends of the grid frame surrounding the ceramic sleeve and resting on said second pair of washers, said cathode having a tab connected with another of the leads of the stem with said filament connected with still other leads, a third pair of washers like the second pair of washers, a second grid frame, grid wires thereon and a tab connected to a lead, the face of the second grid frame having the grid wires facing the cathode, a fourth pair of washers like the first pair, and a second anode, like the first anode but with the flanges extending upward, also mounted on the pins, the whole assembly assembled and fastened together and forming a compact group of elements.

4. A tube mount and stem, said stem having leads extending therethrough, metallic sleeves fastened to two of said leads at the upper ends thereof with portions of the sleeves extending above the level of the tops of the leads, a pair of pins having their lower ends inserted in the tops of the sleeves and fastened thereto, said pins having fixed bead portions resting on top of said sleeves, a channel shaped anode supported by said beads with the channel sides extending downward and the web in a horizontal plane, said web having a flat topped central portion raised above the general level of the web portion, a long ceramic spacing sleeve about eachof the pins on top of a the anode, a short ceramic washer about each of said sleeves and resting on the anode, a flat grid frame with lateral grid wires on the face of the frame away from the anode and having notched ends partially surrounding the ceramic sleeves and resting on the ceramic washers, said raised portion on the anode extending close to the frame but out of contact therewith, a heat radiating and electro-conductive tab fastened to a side of said grid frame and fastened to another one of the leads of the stem, a second pair of washers surrounding the ceramic sleeves, a cathode assembly comprising opposed dished plates securely fastened together forming a hollow interior with an insulated heater between the plates and with notched ends symmetrical with the notched ends of the grid frame surrounding the ceramic sleeve and slidably resting on said second pair of washers, said cathode having a tab connected with another of the leads and said filament being connected with still other leads, a third pair of washers like the second pair of washers, a second grid frame, grid wires thereon and a tab connected to a lead, the face of the grid frame having the grid wires facing the cathode, a fourth pair of washerslike the first pair, and a second anode, like the first anode but with the flanges extending upward, also mounted on the pins, the whole assembly fastened together and forming a compact easily assembled group of elements.

5. A tube mount including a stem with leads extending therethrough, metallic sleeves fastened to two of said leads at the upper ends thereof with portions of the sleeves extending above the level of the tops of the leads, a pair of pins having their lower ends inserted in the tops of the sleeves and fastened thereto, said pins having fixed lateral extrusions resting on top of said sleeves, a channel shaped anode supported by said extrusions with the channel sides extending downward and the web in a horizontal plane, said web having a flat topped central portion raised above the general level of the web portion, a long ceramic spacing sleeve about each of the pins on top of the anode, a short ceramic washer about each of said sleeves and resting on the anode, a fiat grid frame with lateral grid wires on the face of the frame away from the anode and having notched ends partially surrounding the ceramic sleeves and resting on the ceramic washers, said raised portion of the anode extending close to the frame but out of contact therewith, a heat radiating an electro-conductive tab fastened to a side of said grid frame and fastened to another one of the leads of the stem, a second pair of washers surrounding the ceramic sleeves, a cathode assembly comprising opposed dished plates securely fastened together forming a hollow interior with an insulated heater therebetween and with notched ends symmetrical with the notched ends of the grid frame surrounding the ceramic sleeve and slidably resting on said second pair of washers, said cathode having a tab connected with another of the leads and said filament being connected with still other leads, a third pair of washers like the second pair of washers, a second grid frame, grid wires thereon and a tab connected to a lead, the face of the grid frame having the grid wires facing the cathode, a fourth pair of washers like the first pair, and a second anode, like the first anode but with the flanges extending upward, also mounted on the pins, the whole assembly being fastened together and forming a compact easily assembled group of elements, said first anode being insulated from one of said pins and the second anode being insulated from the other of said pins.

6. A cathode structure comprised of two dished plates securely fastened together, said plates being essentially rectangular in plan, each plate having straight channels, semi-circular in cross-section, leading diagonally from the dished portion of the plate to the corners of the plate, the hollows of the plates facing one another and providing a hollow central space and circular ducts leading from the central space to the exterior of the plates, and an insulated filament snugly arranged within the hollow space with leads extending through a pair of the circular ducts.

7. A cathode structure comprised of two dished plates securely fastened together, said plates being essentially rectangular in plan, each plate having straight channels, semi-circular in cross-section, leading diagonally from the dished portion of the plate to the corners of the plate, the hollows of the plates facing one another and providing a hollow central space and circular ducts leading from the central space to the exterior of the plates, and an insulated filament snugly arranged within the hollow space with leads extending through the circular ducts, two opposite edges of the plate being semi-circularly recessed to fit between a pair of spacing insulators.

8. A tube mount comprising support pins, an anode having a central raised portion mounted thereon, an insulating cylindrical sleeve on each of said pins and an array of insulating washers and electrodes, said elec-' trodes having notches at least as wide as the diameter of the sleves, with the spacing between the bights of the notches less than the spacing between sleeves, said array including a cathode, positioned by said sleeves, the washers constituting spacers between electrodes and the notches of the electrodes constituting means to prevent undesired shifting of the electrodes on the washers, while yet permitting longitudinal expansion of the cathode, when heating.

9. A tube mount including vertical supports, insulating washers on said supports, elements stacked on said vertical supports and between said insulating washers, one of said elements comprising an elongated cathode of two dished plates accommodating a heating filament therebetween, the dished plates being secured together along substantially their entire outer periphery and making a rigid structure and provided with recessed ends at the longitudinal ends of the cathode, said recessed ends embracing the supports between the washers and slidable between the washers and allowing for longitudinal expansion of the cathode on heating.

10. A tube mount including vertical supports, insulating washers on said supports, elements stacked on said vertical supports and between said insulating washers, one of said elements comprising an elongated cathode of two dished plates accommodating a heating filament therebetween, the dished plates being secured together along substantially their entire outer periphery to make a rigid structure and provided with opposed semi-circular portions leading from the dished portions diagonally to edges of the cathode to reinforce the cathode and to electrostatically shield the filament, said cathode being further provided with recessed ends at the longitudinal ends of the cathode, said recessed ends embracing the supports between the washers and slidable between the washers and allowing for longitudinal expansion of the cathode on heating.

References Cited in the file of this patent UNITED STATES PATENTS 2,202,607 Steudel May 28, 1940 2,254,727 Beggs Sept. 2, 1941 2,381,632 Watrous Aug. 7, 1945 2,441,792 Brian May 18, 1948 2,459,277 Halstead et a1. Jan. 18, 1949 2,468,417 Stutsman Apr. 26, 1949 2,592,549 Ekstrand Apr. 15, 1952 

